To support a long-term NOAA Coral Reef Conservation Program (CRCP) for sustainable management and conservation of coral reef ecosystems, from 15 April - 7 May 2009, reef fish assessment surveys were conducted, as a part of Rapid Ecological Assessments (REA), during the Pacific Reef Assessment and Monitoring Program (RAMP) Cruise HI0903 in the Marianas Archipelago at biennial intervals by the Coral Reef Ecosystem Division (CRED) at the NOAA Pacific Islands Fisheries Science Center (PIFSC). During the cruise, 7 REA sites were surveyed at Farallon De Pajaros Island in the Marianas Archipelago.
At the specific REA sites, fish biologists along with coral biologists, algal biologists and marine invertebrate zoologist entered the water and conducted a fine-scale (~300 m2) and high degree of taxonomic resolution REA survey to assess and monitor species composition, abundance, percent cover, size distribution, diversity, and general health of fish, corals, macro-invertebrates, and algae in shallow-water (< 35 m) habitats.
Reef fish assessment surveys were focused on cataloging the diversity (species richness), abundance (numeric density [# fish 100 m-2] and biomass density [kg 100 m-2]) of diurnally active reef fish assemblages. Three complementary noninvasive underwater survey methods were used, including belt-transect, stationary point count, and roving-diver surveys. For all methods, fish were identified at the species level, when possible, and assigned to a size bin ranging from 1 to 200 cm based on a visual estimate of total fish length.
Belt-transect (BLT) surveys were used to quantify the entire diurnal fish community (all size classes). In belt-transect surveys, two fish biologists swam side-by-side along three consecutively-placed, 25m transect lines. The BLT team swam each transect two times. During the initial swim-out, each fish diver recorded all fish larger than 20 cm observed within a 4-m wide belt perpendicular to their respective side of the transect (200 m2 area per line, 100 m2 per diver). On the return swim, each fish diver recorded all fish less than 20 cm observed within a 2-m wide belt (100 m2 area per line, 50 m2 per diver). The survey of large fish took approximately 5 min to complete while the survey of smaller fish took about 10 min to complete. All reef-associated fish, including those in the water column (including planktivores), were counted. Any coastal pelagic species (e.g., clupeids [sardines], belonids [beakfish], antherinids [silversides]) seen near the surface were not recorded.
The stationary point count (SPC) method were used to quantify larger, more mobile reef fish species that can be missed on belt-transect surveys. In stationary point count survey, a fish biologist swam approximately 15 m away from a transect line concurrently being surveyed by the other two BLT fish biologists. The SPC biologist then recorded all fish greater than 25 cm in length that passed within a visually estimated 20-m diameter cylinder centered on the diver's fixed position (10-m radius, total area = 314 m2). The survey time for each stationary point count survey was 5 min and a total of four stationary point count surveys were conducted at each REA site.
Roving-diver surveys were followed belt-transect and stationary point count surveys. As diver bottom time permitted, the fish assessment team conducted random swim surveys throughout the REA site area, recording, to the species level or the lowest recognizable taxon, the presence of reef fish not encountered during previous methods.

Purpose:

Part of a long-term monitoring program at biennial intervals which documents the state of the reefs.

Observations at each site were made by three divers who are experts in fish taxonomy. The team of three REA fish divers rotated roles with two divers performing belt-transect surveys and one diver performing stationary point counts at each survey site. Observations were periodically checked during the expedition for consistency between divers, and little discrepancy was ever noted between divers. It should be noted, however, that this data set is quite large, and probably includes typographical or other errors that might be discovered at a future date.

Logical_Consistency_Report:

The same methods of data collection were used at each of the sites surveyed at this location, and were conducted by the same scientists. Periodic examination of the data through the duration of the trip showed no signs of diver bias or other discrepancies.

Completeness_Report:

The survey sites were selected to be representative of the coral reef habitats at this reef system. Efforts were made to include broad spatial coverage of the reef area, but weather conditions or other environmental constraints may have precluded the team from surveying windward or exposed sites.

REA surveys are investigations that provide a high degree of taxonomic resolution for coral, algae, other macroinvertebrate, and reef fish communities. The surveys were conducted using a combination of dive teams which generally included a two to three person fish team, a two person coral/coral disease team, and a combined team of two algae biologists and one macroinvertebrate biologist. The majority of REA surveys were conducted along the forereef slopes of individual islands at depths between 10 and 20 m. However, additional surveyed habitats included a lagoonal-type patch reef and offshore oceanic banks.
During REA surveys, biological assessment teams follow highly structured protocols that are repeated at each REA site. Upon arrival at an REA site, three teams of divers enter the water over spaced time intervals. The fish team firstly enters the water and deploys a 25-m transect line. Two of the fish divers begin to survey along that transect while the remaining fish diver begins stationary point count assessments in the general vicinity. After approximately 20 min, the coral team enters the water and begins to work along the first transect line. By this time the fish team has deployed and begun surveys along a second 25-m transect. About 10 min later, the algal/invertebrate team enters the water and begins surveying the first transect. In total, the fish team surveys three transects at each site (transects 1, 2, and 3), and the coral and algal/invertebrate teams survey transects 1 and 2. The sampling effort takes between 60 and 80 min to complete.
The selection of REA sites was made in close consultation with Coral Reef Advisory Group (CRAG) and local agencies. Factors considered during REA site selection included: (1) ensuring a range of sample sites representative of the benthic and reef fish habitats around each island; (2) selecting a mixture of sites within and outside of marine protected areas; (3) selecting a mixture of both 'impacted' and 'least impacted' sites; (4) selecting some sites adjacent to local villages, and (5) selecting a number of sites that could be compared to and complement previous assessment and monitoring work as well as future coral reef monitoring proposed by CRAG and local agencies. It is important to note that access to REA sites can be limited by wave exposure, weather conditions, and other environmental factors such as currents, which can affect the ability to resurvey sites between years.
Transect placement was guided by: (1) a focus on hard-bottom communities; (2) deploying lines along an isobath to the extent possible at each site, and (3) laying the transect lines into the prevailing current.

While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.